This invention relates to an apparatus and process for joining films, particularly laminate films each comprising a thermoplastic drawn base film layer and a sealant layer and used, for example, as a film for package, and proposes a technique in which the joint portion of the films is subjected to a liquid-tight and airtight heat sealing likewise the other film portion in the manufacture of package bag or the like.
For example, a film for package used in a case of continuously filling and packaging a liquid, a powder or the like or a case of intermittently filling and packaging it and supplied in the manufacture of a package bag filled with a material to be filled, particularly laminate film for package is generally applied through printing step, laminating step and slitter step to an automatic filling and packaging apparatus at a state of winding in the form of roll.
In the slitter step, the cutting removal of side portions of the film is carried out for mainly making a width size of a laminate film for package after the lamination but also the laminate films for package are joined with each other in order to adjust a length of the film to be wound in the form of roll to render a total winding length of the film into, for example, a given length such as 1000 m, 2000 m or the like, and the joining of the films is conducted after a poor printed portion or a poor laminated portion is removed by cutting. For this end, about 2 to 3 joint portions of the films are existent in the wound film of 2000 m.
Also, in the packaging step for applying the laminate film for package having a specific rolled length to an automatic filling-packaging apparatus to conduct the filling and packaging of a material to be packaged, a rear end portion of a preceding film for package fed from a roll is joined to a front end portion of a trailing film for package fed from another roll, whereby the trailing film for package is passed through a given pathway of a packaging apparatus.
The joining between mutual films at the slitter step is carried out by joining these films with an adhesive tape or the like at a state of butting the rear end of one film to the front end of the other film from the old time. Also, the film joining at the filling and packaging step is carried out by overlap-joining the rear end portion of the one film to the front end portion of the other film with an adhesion tape or the like.
However, when the thus joined laminate film for package is applied to the packaging apparatus to manufacture a package bag, the adhesion tape or the like made of a material different from the laminate film for package, or the overlap of the front and rear end portions of the laminate films for package in addition to the adhesion tape or the like brings about the increase of the thickness in the laminate film for package at the joint portion of the films and also the sufficient heat transfer from a heat seal blade of the packaging apparatus to a sealant layer of a film portion contributing to the formation of the package bag is obstructed by properties inherent to the adhesive tape or the like, so that it is substantially impossible to rapidly fuse the sealant layer to a sufficient extent of fusing the mutual sealant layers.
When the continuous filling and packaging of a material to be packaged is carried out, for example, by the above laminate film for package, even if it is possible to pass the joint portion between the films through a space between a longitudinal heat seal blade and a lateral heat seal blade as a pair of rotational seal blades rotating at a constant clearance as it is, the sealant layers can not be sufficiently heat-fused due to the presence of the adhesion tape, increase of total film thickness and the like even under the heating and pressurizing action of the heat seal blades, so that there is a problem of causing leakage, scattering and the like of a liquid or other material to be packaged in the packaging apparatus.
This is also caused in a case that the joint portion is particularly located in a middle part of the package bag in up-down directions due to the fact that the mutual laminate films for package can not be joined by the adhesion force of the adhesion tape at a strength required for the package bag with sufficient liquid tightness and airtightness.
Heretofore, the whole of the packaging device or the function of a main part such as heat seal functioning part, filling part and the like is temporarily stopped at every feeding of the joint portion between the laminate films for package from the wound roll and at every film joining at the packaging device, and the filling and packaging are re-opened after the film joint portion is passed through the main part of the device. In the re-opening, the confirmation of amount of a material to be packaged in the package bag, confirmation of heat seal position and sealing state, confirmation of cutting position of the package bag and forming position of tear notch are conducted and all of them are placed within an acceptable range and thereafter the device is fully re-operated.
Therefore, there is a big problem in the operation efficiency that many time and operation steps are required over a time ranging from the temporary stop of the device as a whole or main functioning part thereof to the re-operation of the device but also there is a problem that the yield of the material lowers due to the fact that it is obliged to consume significant amounts of the laminate film for package and the material to be packaged owing to the above various confirmations.
It is, therefore, an object of the invention to provide an apparatus and a process for joining of films suitable for both of the slitter step and the packaging step, in which the mutual joining between the rear end portion of one film and the front end portion of another film are carried out without using a joining material such as adhesion tape or the like and the resulting joint portion is sufficiently contributed to the heat seal likewise the other portion of the film and the liquid tightness and airtightness of the joint portion itself are realized and further the tensile strength required to the film itself is given to the joint portion to effectively enhance the efficiency of the filling and packaging operation for the material to be packaged as a film for package and also the field of the material can be largely increased.
The apparatus for joining films according to the invention lies in that a rear end portion of a preceding film for package fed from a winding roll is joined to a front end portion of a trailing film for package fed from another roll, and comprises a seal means for fuse-sealing both films at a butt-seam state in the vicinity of the film running path or in the vicinity of any one of up and down and right and left portions, a film-holding means for holding the front end portion of the trailing film at a side opposite to the seal means with respect to the running path by clamping, adsorbing or the like, an insert plate for pushing the front end portion of the trailing film held by the film-holding means into the seal means together with the preceding film, and an extra film removing means for separating a turnup portion of the film pushed by the insert plate over the seal means at a clamped state from a fuse-sealed portion of the films.
In this apparatus, the rear end portion of the preceding film and the front end portion of the trailing film held by the film-holding means are pushed into the seal means by the action of the insert plate, respectively, and the turnup portion of the films pushed over the seal means is clamped by the extra film removing means and thereafter both the films are fuse-joined in a butt-seam form by the action of the fuse-seal means at a posture state of moving the insert plate backward, and subsequently the extra film removing means is moved in a direction separating away from the seal means to separate the film turnup portion from the fuse-sealed portion, whereby both the films can be joined to each other, and also the thus formed fuse-sealed portion has a high joining strength and can develop excellent airtightness and liquid tightness.
Further, the increase of film thickness at the joint portion can be effectively prevented by separating and removing the extra projected portion from the butt-seal fuse-sealed portion between both the films.
Therefore, when the mutual joining of the films for package is carried out by the above apparatus, the joining material such as adhesion tape or the like is naturally useless but also the film joint portion can be stationarily passed through the packaging device without stopping the function thereof or the like irrespectively of the joint portion produced at the slitter step or the joint portion produced at the filling and packaging step of the material to be packaged, whereby the film joint portion is sufficiently heat-fused under heating and pressing through the heat seal blade without obstructing by the increase of the film thickness and the joining material and hence such a joint portion can sufficiently contribute to the preparation of the packaging bag likewise the other portion of the film for package to develop an excellent heat seal strength.
Furthermore, the film joint portion itself has high liquid tightness and airtightness in addition to the sufficient tensile strength, so that even if the joint portion crosses the packaging bag at the middle part in the up-down directions of the packaging bag, the fear of leaking the material to be packaged therefrom or the like.
Thus, the operation efficiency in the filling and packaging of the material to be packaged can be effectively enhanced, and also the yields of the film for package and the material to be packaged can be largely improved.
When the film-holding means itself is made possible to move forward and backward to the seal means, the front end portion of the trailing film can be more easily held by the film-holding means of the backed posture without fearing the interference of the preceding film or the like.
Also, when the seal means is constructed with a pusher pushing the heater, the film to the heater or the heater to the film, the pushing of the film into the seal means through the insert plate can be sufficiently facilitated and further the proper fuse sealing can be surely conducted as is expected.
The heater is preferable to be an impulse sealer. In this case, the fuse sealing is conducted in a very short time by instant heat generation through impact current and also the fuse-sealed portion can be cooled in a short time, so that when the film is particularly provided with a thermoplastic drawing base film layer, the heat deformation of such a film layer and hence the film as a whole can be effectively prevented.
Furthermore, the film-holding means is arranged in a block moving forward and backward to the seal means, for example, lifting up and down thereto and can be constructed by a clamping plate opening and closing through an actuator or a manual operation.
The clamping of the front end portion of the film by the clamping plate can be further surely carried out under a small energy consumption as compared with the adsorption holding under a negative pressure or the like and has a merit of causing no noise. Therefore, the clamping plate is arranged in the block lifting up and down between the operating position and waiting position of the seal means, whereby the clamping of the front portion of the film through the clamping plate can be carried out safely, surely and easily at the waiting position and at the required timing.
When the actuator moving forward and backward the insert plate to the seal means is arranged in the block, the insert plate can also be moved between the position of obstructing no running of the film during the feed running and the position of operating it based on the forward and backward movement of the block, and the film can be pushed into the seal means by a small linear going stroke of the insert plate itself.
Further, the extra film removing means can be constructed with a pivoting arm moving in a direction separating from the seal means and a clamper arranged on the pivoting arm and moving forward and backward therewith.
According to this means, the turnup portion of the film can be clamped in the pivoting arm by forward moving the clamper operated, for example, with an air cylinder in agreement with the timing of the forward movement of the insert plate. In this case, such a clamping state is continued until the insert plate is moved backward to conduct the fuse sealing and the pivot arm is separated from the seal means to completely separate and cut the extra turnup portion of the film from the fuse sealed part.
In this case, the clamping of the film, which is pushed into the extra film removing means at a bending state through the insert plate, into the pivot arm without interference to the insert plate can be carried out by constructing the clasper with plural rod-shaped members moving forward through top notched parts formed in the insert plate and clamping the turnup portion of the film at places corresponding to the notched parts of the insert plate through these rod-shaped members.
In the above apparatus, it is more preferable to arrange at least one accumulate roll guaranteeing the feeding out of the preceding film at a given rate during the joining operation between both the films.
Thus, when the apparatus is applied to, for example, the slitter step, packaging step and the like of the film for package, the joining operation of the films can be conducted without stopping the steps.
More preferably, a film feeding roll is arranged at a downstream side of the accumulate roll to always ensure the steady feeding of the film.
In this case, it is preferable to arrange a stop roll clamping the film and stopping the feed running thereof between the seal means and the accumulate roll, while a length-adjusting roll producing the loosening of the film is arranged between the stop roll and the seal means.
According to this structure, the constant feeding of the preceding film is carried out by the action of the one or more accumulate rolls under the restraint of the film movement through the stop roll in the joining operation of the films, and also the length of the film required for pushing the film from the seal means to the extra film removing means is ensured by the action of the length adjusting roll, whereby the film joining is surely conducted based on the complete separation in the function between the accumulate roll and the length adjusting roll as is expected and the steady feeding of the film can be conducted in a higher accuracy.
That is, when only the accumulate roll is arranged as the stop roll, length adjusting roll or the like, it is required that the accumulate roll is operated at a high speed at a first time of the start of the film joining operation to feed the film stored therein for the steady feeding and for the pushing of the film into the seal means or the like, but it is difficult to always and properly control the high operating speed of the accumulate roll owing to difference of properties such as elastic modulus, mass and the like in accordance with the kind of the film. Also, after the pushing of the film into the seal means or the like is completed, it is required to necessarily decrease the operating speed of the accumulate roll, but it is difficult to prevent the occurrence of position shifting at the downstream side operation due to the change of tension in the fed film based on the decrease of the speed. On the contrary, when the stop roll and the length adjusting roll are arranged, the accumulate roll can be always operated at the constant speed under the function separation between the accumulate roll and the length adjusting roll to feed the film at a given speed, and also the loosening required for the joining of the films can be surely generated by the length adjusting roll, so that there can be advantageously removed the inconvenience when these rolls are not arranged.
The method of joining films according to the invention lies in that when the rear end portion of the preceding film and the front end portion of the trailing film are joined to each other by the apparatus mentioned above, an insert plate is moved forward during the feed running of the preceding film to push the front end portion of the trailing film held by a film-holding means together with the preceding film into a seal means over a given length, and then a turnup portion of the film pushed over a position of the seal means is clamped with an extra film removing means, and thereafter both the films are fuse-sealed in a butt-seam form by the seal means while changing the insert plate backward, and further the turnup portion of the film is separated from a fuse-sealed portion by pivotably moving the extra film removing means.
According to this method, the joining of the mutual films is carried out simply, rapidly and surely, and can be easily automated. Also, when the steady feeding of the film is guaranteed by the accumulate roll, the joining can be continued without stopping the operation of the slitter packaging or the like even in the joining operation of the film.
Moreover, when the front end portion of the trailing film previously held by the film-holding means is moved to a position near to the seal means prior to the forward moving of the insert plate, the holding of the front end portion of the film with the holding means can be carried out safely, surely and easily at a given timing without the interference of the running film.
When each of the films to be mutually joined is a film provided with a thermoplastic drawing base film layer and a sealant layer, the drawing base film layers of both the films can be fused in a butt-seam form by the seal means but also the sealant layers can be fused with each other. In the former case, the joint strength can be highly increased, and in the latter case, the influence of the projection portion of the fuse-cut sealed part upon the packaging operation can be lessened.
Further, when the films are fused by the impulse fuse sealing, the thermal deformation of the drawing base film layer can be advantageously suppressed by rapidness of the heating and cooling.